2of 5A's Matt Chapman, 26 walks back to the dugout after being called out looking to end the sixth inning as home plate umpire Jordan Baker barks back at Chapman, as the Oakland Athletics take on the Los Angeles Angels at the Oakland Coliseum in Oakland, Ca. on Mon. September 4, 2017.Photo: Michael Macor, The Chronicle

3of 5OAKLAND, CA - SEPTEMBER 06: Home plate umpire Mike Everitt stands in between Matt Chapman #26 of the Oakland Athletics and Juan Graterol #13 of the Los Angeles Angels in the fourth inning at Oakland Alameda Coliseum on September 6, 2017 in Oakland, California. Chapman was ejected on the play. (Photo by Ezra Shaw/Getty Images)Photo: Ezra Shaw, Getty Images

4of 5OAKLAND, CA - SEPTEMBER 06: Manager Bob Melvin argues with home plate umpire Mike Everitt after Matt Chapman #26 of the Oakland Athletics was ejected from the game after having words with Juan Graterol #13 of the Los Angeles Angels in the fourth inning at Oakland Alameda Coliseum on September 6, 2017 in Oakland, California. (Photo by Ezra Shaw/Getty Images)Photo: Ezra Shaw, Getty Images

5of 5OAKLAND, CA - SEPTEMBER 06: Manager Bob Melvin argues with home plate umpire Mike Everitt after Matt Chapman #26 of the Oakland Athletics was ejected from the game after having words with Juan Graterol #13 of the Los Angeles Angels in the fourth inning at Oakland Alameda Coliseum on September 6, 2017 in Oakland, California. (Photo by Ezra Shaw/Getty Images)Photo: Ezra Shaw, Getty Images

Rookie third baseman Matt Chapman was ejected from Wednesday’s game in the fourth inning after a testy exchange with Angels catcher Juan Graterol that A’s outfielder Khris Davis said exemplified what a team leader Chapman is becoming.

Chapman said he was trying to stick up for teammates Graterol had accused of stealing signs. “I think this stemmed back to a couple of days ago. They thought we were relaying signs from second base and they also thought a couple of hitters were peeking at catchers’ signs,” Chapman said.

“When we were digging into the box today, the catcher kept staring at the hitters as they were digging into the box. That’s not a very comfortable feeling having the catcher staring at you. It’s a little disrespectful. So when I got into the box, I just let them know we were not stealing signs and there was no need to be staring at us. He obviously didn’t take too kindly to that.”

Davis, who hit his AL-leading 39th homer Wednesday, said that Chapman “is a leader. He’s a natural at it. He might be a rookie but one day, he’s going to lead the way.”

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In the second inning, Graterol snapped at Oakland outfielder Mark Canha; home-plate umpire Mike Everitt got between them and Everitt could be heard telling the Angels’ dugout that there were accusations of stealing signs.

“I don’t know if it’s their pre-pitch routine, but they have a habit of glancing back,” Angels manager Mike Scioscia said. “On a day game or a night game when you can see shadows and a catcher’s head, it’s easy to look back and pick up some locations. So, Juan was just saying, ‘Hey, man, don’t look back.’”

“We have video on what they do,” Angels starter Tyler Skaggs said. “If they need to look at signs to hit, it is what it is.”

Canha said that Graterol told him, “Stop looking at my signs,” and he had done the same thing to Chad Pinder. “Chad’s not the type of guy who would do that. I’ve never done that in my career,” Canha said. “I thought it was just a Scioscia-Angels-Graterol tactic to make young players get uncomfortable, just get in my head. I was just like, ‘OK, play your little games and I’m just going to focus on the task at hand.’”

Chapman wasn’t having it, but he said he used no swear words in the fourth when he spoke to Graterol. Graterol sprang to his feet and Everitt immediately separated them.

Everitt then gave Chapman a bit of a lecture, which is unusual. One scout said he found it “disrespectful. He’d never do that with an older player.”

“He said it had already been handled,” Chapman said of Everitt. “But obviously if I’d thought it had been handled, I wouldn’t have said anything. If it had been handled, (Graterol) wouldn’t have been continually staring at us when we were getting in the box. Obviously, I didn’t intend for it to go down like this, but the way I looked at it, I wanted to stand up for my teammates and for myself.

“Even though we are a young group of guys, I feel we deserve to be treated just like anyone else in the big leagues and be respected by our opponents.”

“It’s a nice thing to do, but I told him I’d rather have him in the game than sticking up for me,” Canha said.

The scout said that, in fact, he believed the Angels to be stealing signs during the top of the second inning.

Asked if the matter is over, Canha said he wasn’t sure. The teams do not play again until next spring.

Susan Slusser has worked at The San Francisco Chronicle since 1996. She has been a member of the Baseball Writers Association of America since 1993 and in 2012 became the only woman to be elected president in the 111 years of the organization. She has written about many other sports for the paper, particularly hockey and, more recently, e-sports.

Susan previously covered the Texas Rangers for the Dallas Morning News, the Orlando Magic for the Orlando Sentinel, and the NBA and other sports for the Sacramento Bee.

Susan is an on-air correspondent for the MLB Network and makes regular appearances on 95.7 FM The Game. Her book about the A’s, 100 Things A's Fans Need to Know and Do Before They Die, came out in 2014 and she and A’s radio announcer Ken Korach are working on a book that will come out in 2019.